target/linux/ramips/patches-4.9/100-mt7621-core-detect-hack.patch

   1 There is a variant of MT7621 which contains only one CPU core instead of 2.
   2 This is not reflected in the config register, so the kernel detects more
   3 physical cores, which leads to a hang on SMP bringup.
   4 Add a hack to detect missing cores.
   5
   6 Signed-off-by: Felix Fietkau <nbd@nbd.name>
   7
   8 --- a/arch/mips/kernel/smp-cps.c
   9 +++ b/arch/mips/kernel/smp-cps.c
  10 @@ -56,6 +56,11 @@ static unsigned core_vpe_count(unsigned
  11         return (cfg >> CM_GCR_Cx_CONFIG_PVPE_SHF) + 1;
  12  }
  13
  14 +bool __weak plat_cpu_core_present(int core)
  15 +{
  16 +       return true;
  17 +}
  18 +
  19  static void __init cps_smp_setup(void)
  20  {
  21         unsigned int ncores, nvpes, core_vpes;
  22 @@ -66,6 +71,8 @@ static void __init cps_smp_setup(void)
  23         ncores = mips_cm_numcores();
  24         pr_info("%s topology ", cpu_has_mips_r6 ? "VP" : "VPE");
  25         for (c = nvpes = 0; c < ncores; c++) {
  26 +               if (!plat_cpu_core_present(c))
  27 +                       continue;
  28                 core_vpes = core_vpe_count(c);
  29                 pr_cont("%c%u", c ? ',' : '{', core_vpes);
  30
  31 --- a/arch/mips/ralink/mt7621.c
  32 +++ b/arch/mips/ralink/mt7621.c
  33 @@ -17,6 +17,7 @@
  34  #include <asm/mips-cpc.h>
  35  #include <asm/mach-ralink/ralink_regs.h>
  36  #include <asm/mach-ralink/mt7621.h>
  37 +#include <asm/mips-boards/launch.h>
  38
  39  #include <pinmux.h>
  40
  41 @@ -164,6 +165,20 @@ void __init ralink_of_remap(void)
  42                 panic("Failed to remap core resources");
  43  }
  44
  45 +bool plat_cpu_core_present(int core)
  46 +{
  47 +       struct cpulaunch *launch = (struct cpulaunch *)CKSEG0ADDR(CPULAUNCH);
  48 +
  49 +       if (!core)
  50 +               return true;
  51 +       launch += core * 2; /* 2 VPEs per core */
  52 +       if (!(launch->flags & LAUNCH_FREADY))
  53 +               return false;
  54 +       if (launch->flags & (LAUNCH_FGO | LAUNCH_FGONE))
  55 +               return false;
  56 +       return true;
  57 +}
  58 +
  59  void prom_soc_init(struct ralink_soc_info *soc_info)
  60  {
  61         void __iomem *sysc = (void __iomem *) KSEG1ADDR(MT7621_SYSC_BASE);